Question

Observe the figure of a current carrying solenoid.

• [(a)] What is meant by a solenoid?
• [(b)] The end connected to the positive terminal of the cell will always be the North pole of a solenoid. Is this statement correct? Justify your answer.
• [(c)] Write any two ways to increase the strength of the magnetic field formed around a current carrying solenoid.

Hint:

More current + more turns + iron core → stronger magnetic field

Answer 1

(a) Definition of solenoid
A solenoid is a long cylindrical coil of many closely wound turns of insulated copper wire through which electric current flows. (b) Correctness of statement
Step 1: Concept of polarity}
The polarity of a solenoid depends on the direction of current. Step 2: Right-hand thumb rule}
If we curl the fingers of the right hand in the direction of current, the thumb points towards the North pole. Step 3: Conclusion}
The given statement is incorrect because:

• The terminal connected to positive does not always become North.
• It depends on the direction of current in the coil.

Final Answer (b): \[ \text{Statement is incorrect} \] (c) Ways to increase magnetic field strength
Step 1: Methods}}

• Increase the current through the solenoid
• Increase the number of turns (coils)
• Insert a soft iron core inside the solenoid

Any two: \[ \text{Increase current and increase number of turns} \]